linux-kernel - Re: [PATCH v4 18/20] ACPI: platform

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <cbf90e6e-1522-4235-b1fd-90dc54df35d5@gmx.de>
Date: Wed, 6 Nov 2024 20:33:04 +0100
From: Armin Wolf <W_Armin@....de>
To: Mario Limonciello <mario.limonciello@....com>,
 Hans de Goede <hdegoede@...hat.com>,
 Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
 Maximilian Luz <luzmaximilian@...il.com>, Lee Chun-Yi <jlee@...e.com>,
 Shyam Sundar S K <Shyam-sundar.S-k@....com>,
 Corentin Chary <corentin.chary@...il.com>, "Luke D . Jones"
 <luke@...nes.dev>, Ike Panhc <ike.pan@...onical.com>,
 Henrique de Moraes Holschuh <hmh@....eng.br>,
 Alexis Belmonte <alexbelm48@...il.com>,
 Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
 Ai Chao <aichao@...inos.cn>, Gergo Koteles <soyer@....hu>,
 open list <linux-kernel@...r.kernel.org>,
 "open list:ACPI" <linux-acpi@...r.kernel.org>,
 "open list:MICROSOFT SURFACE PLATFORM PROFILE DRIVER"
 <platform-driver-x86@...r.kernel.org>,
 "open list:THINKPAD ACPI EXTRAS DRIVER"
 <ibm-acpi-devel@...ts.sourceforge.net>,
 Mark Pearson <mpearson-lenovo@...ebb.ca>,
 Matthew Schwartz <matthew.schwartz@...ux.dev>
Subject: Re: [PATCH v4 18/20] ACPI: platform_profile: Allow multiple handlers

Am 06.11.24 um 20:21 schrieb Armin Wolf:

> Am 05.11.24 um 16:33 schrieb Mario Limonciello:
>
>> Multiple drivers may attempt to register platform profile handlers,
>> but only one may be registered and the behavior is non-deterministic
>> for which one wins.  It's mostly controlled by probing order.
>>
>> This can be problematic if one driver changes CPU settings and another
>> driver notifies the EC for changing fan curves.
>>
>> Modify the ACPI platform profile handler to let multiple drivers
>> register platform profile handlers and abstract this detail from
>> userspace.
>>
>> To avoid undefined behaviors only offer profiles that are commonly
>> advertised across multiple handlers.
>>
>> If any problems occur when changing profiles for any driver, then revert
>> back to the balanced profile, which is now required.
>
> Reviewed-by: Armin Wolf <W_Armin@....de>
>
I just noticed that the following text might need to be removed:

"If any problems occur when changing profiles for any driver, then revert
  back to the balanced profile, which is now required."

Thanks,
Armin Wolf

>> Tested-by: Matthew Schwartz <matthew.schwartz@...ux.dev>
>> Reviewed-by: Mark Pearson <mpearson-lenovo@...ebb.ca>
>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
>> ---
>>   drivers/acpi/platform_profile.c | 12 ++----------
>>   1 file changed, 2 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/acpi/platform_profile.c
>> b/drivers/acpi/platform_profile.c
>> index 568485e285061..b9eb25f58a2a2 100644
>> --- a/drivers/acpi/platform_profile.c
>> +++ b/drivers/acpi/platform_profile.c
>> @@ -10,7 +10,6 @@
>>   #include <linux/platform_profile.h>
>>   #include <linux/sysfs.h>
>>
>> -static struct platform_profile_handler *cur_profile;
>>   static DEFINE_MUTEX(profile_lock);
>>
>>   static const char * const profile_names[] = {
>> @@ -368,8 +367,7 @@ static const struct attribute_group
>> platform_profile_group = {
>>
>>   void platform_profile_notify(void)
>>   {
>> -    if (!cur_profile)
>> -        return;
>> +    guard(mutex)(&profile_lock);
>>       if (!class_is_registered(&platform_profile_class))
>>           return;
>>       sysfs_notify(acpi_kobj, NULL, "platform_profile");
>> @@ -428,9 +426,6 @@ int platform_profile_register(struct
>> platform_profile_handler *pprof)
>>       }
>>
>>       guard(mutex)(&profile_lock);
>> -    /* We can only have one active profile */
>> -    if (cur_profile)
>> -        return -EEXIST;
>>
>>       if (!class_is_registered(&platform_profile_class)) {
>>           /* class for individual handlers */
>> @@ -451,9 +446,9 @@ int platform_profile_register(struct
>> platform_profile_handler *pprof)
>>       if (IS_ERR(pprof->class_dev))
>>           return PTR_ERR(pprof->class_dev);
>>       dev_set_drvdata(pprof->class_dev, pprof);
>> +
>>       sysfs_notify(acpi_kobj, NULL, "platform_profile");
>>
>> -    cur_profile = pprof;
>>       return 0;
>>
>>   cleanup_class:
>> @@ -467,13 +462,10 @@ int platform_profile_remove(struct
>> platform_profile_handler *pprof)
>>   {
>>       guard(mutex)(&profile_lock);
>>
>> -    cur_profile = NULL;
>> -
>>       sysfs_notify(acpi_kobj, NULL, "platform_profile");
>>
>>       device_destroy(&platform_profile_class, MKDEV(0, pprof->minor));
>>
>> -    cur_profile = NULL;
>>       return 0;
>>   }
>>   EXPORT_SYMBOL_GPL(platform_profile_remove);
>